[Aavso-photometry] AAVSO Alert Notice 369 - U and B photometry errors

[arne]

Dave Lane wrote:
> I just sent Arne a screen capture, but in looking more closely I think I 
> know what is happening...
> 
> If plot a chart with the VSP form set to:
> 
> Name AQ Cmi
> RA: 07 47 27.6 Dec: 06 50 50
> 
> Note that this position is wrong - it is from a previous plotted chart 
> (presumably saved by a cookie).
> 
> What happens is the chart is plotted at the correct position for AQ CMi 
> (ie. the chart plotter ignores the RA/Dec and uses the name for the 
> position lookup).
> 
> When you ask for the table photometry, it ignores the name and uses the 
> stated (wrong) position instead. So clearly there is an inconsistency in 
> how the two programs (chart plotter and photometry table) handle the 
> input data (bug! :-).
> 
> If I blank out the RA/Dec it reports the correct photometry.
> 
> That still means the U and B photometry are out of whack for the 
> previous field (which is for VSX J074727.6+065050).
> 
Yes, the creator of the interface knows about this name vs coordinate
discrepancy.  It was low in the priority queue, but has now been
raised. :-)

The U/B-band photometry discrepancy is caused by another problem that I haven't
seen before, though similar problems have occurred when either the AUID or
the coordinates were in error and an incorrect match between catalog and
compDB was made.  I'll see that it gets solved during the next upload to
the comparison star database (which should take place in a week or two).
Arne